1. Field of the Invention:
The present invention relates to a liquid droplet jetting apparatus which jets liquid droplets.
2. Description of the Related Art:
A liquid droplet jetting apparatus, which is provided with a liquid droplet jetting head for jetting liquid droplets from nozzles, has been hitherto known. The liquid droplet jetting apparatus is occasionally provided with the means for recovering the performance by discharging the foreign matter, the bubble, and/or the viscosity-increased liquid from the nozzles when the liquid droplet jetting performance of the head is deteriorated, for example, due to foreign matter and/or bubble mixed in liquid flow passages, which are provided in the liquid droplet jetting head, and/or liquid which is dried to increase the viscosity in the nozzle.
As for the liquid droplet jetting apparatus described above, Japanese Patent Application Laid-open Nos. 2008-260172 and H10-258531 disclose such an ink-jet recording apparatus that an image or the like is recorded by jetting an ink from nozzles with respect to a recording medium. The ink-jet recording apparatus includes an ink-jet head, a cap member which is brought in tight contact with an ink-jetting surface of an ink-jet head to cover the plurality of nozzles, and a suction pump which is connected to a suction port formed for the cap member. The ink is sucked out from the nozzles by reducing the pressure in the cap member by means of the suction pump in a state in which the plurality of nozzles are covered with the cap member, and thus the foreign matter, the bubble and the like, which are contained in the ink-jet head, are discharged together with the ink (the recovery operation as described above is hereinafter referred to as “suction purge”).
In the case of the ink-jet recording apparatus as described in Japanese Patent Application Laid-open Nos. 2008-260172 and H10-258531, the ink, which is adhered to the ink-jetting surface of the ink-jet head, is wiped out by a wiper after the suction purge (wiping operation). Further, in order to adjust the meniscus of the nozzles after the wiping, flashing (also referred to as “preparatory discharge”) is performed, in which the liquid droplets are jetted from the nozzles prior to the actual recording operation. The ink (discharged ink or waste ink), which is once discharged by the suction purge, is sucked into the nozzles on account of the back pressure in the ink-jet head in some cases, and/or the ink (discharged ink or waste ink) is adhered to the nozzle openings and the ink is sucked by the wiping in other cases. Therefore, the flashing is performed while simultaneously satisfying a purpose to discharge the ink which would be otherwise sucked into the nozzles as described above.
Japanese Patent Application Laid-open Nos. 2008-260172 and H10-258531 disclose the following technique. That is, ink discharge amount during the flashing (hereinafter referred to as “flashing amount”) is allowed to differ depending on the type of the ink to be jetted, without allowing the flashing amount to be identical in relation to all of the nozzles, so that the color mixture is effectively avoided. Specifically, in Japanese Patent Application Laid-open No. 2008-260172, the flashing amount is increased for the nozzles which jet the ink having a large specific gravity as compared with the nozzles which jet the ink having a small specific gravity. Further, in Japanese Patent Application Laid-open No. H10-258531, the higher the brightness (luminosity) of the ink is, the greater the flashing amount is.